When 'Guardians of the Galaxy' was pitched to me, I said, 'I don’t think so.' I just didn’t picture myself getting the role. I didn’t want to go and embarrass myself like I did when I auditioned for G.I. Joe a couple of years previously. I went in there, and halfway through I saw the director’s eyes just glaze over. It made sense — I was a little heavy and out of shape. I was not gonna play someone from G.I. Joe. I did not look like a G.I. Joe action figure come to life.

Fast forward and Pratt is now a bona fide movie star, with Oscar-winning films like "Zero Dark Thirty" and "Moneyball" under his belt. But getting to "action figure" status took hard work — and it has paid off.

"I have more energy. I sleep better. My sex drive is up. Blood's flowing. I'm less susceptible to impulse. I'm in a different mode," the actor says of his current, slimmed down 6-foot-2 frame.

When I was way out of shape, the idea of using whitening strips on my teeth seemed terrible. I have to do that every day? I'll never do it. What you want is instant results when you're out of shape. You want your teeth whitened in 45 minutes with the use of lasers. But when you're in shape, you know it's the result of doing a little bit every day. Moments aren't just moments. A moment might be a week or a month. So instead of 'Boy, I'd love to eat this hamburger right now,' I'm considering a little further into the future. I'm thinking, 'I eat that hamburger and that's 1,200 calories, and I'm gonna work out tomorrow and burn 800 calories. I may as well eat a salad here, still do that workout, and then I'm actually making progress.'

Pratt says he had to sacrifice: "You can't have hash browns, or burgers, or anything fried. You can't have carbs. You have to work out five times a week."

But in the end, it has all been worth it to finally obtain his "action figure" physique: "I can do 40-inch box jumps now. Action-hero physical stuff. Jumping that high feels really good ... When you get in shape, the world around you becomes things you want to jump on and climb on."